Npp1 promotes atherosclerosis in ApoE knockout mice.

Ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) generates inorganic pyrophosphate (PP(i)), a physiologic inhibitor of hydroxyapatite deposition. In a previous study, we found NPP1 expression to be inversely correlated with the degree of atherosclerotic plaque calcification. Moreover, function-impairing mutations of ENPP1, the gene encoding for NPP1, are associated with severe, artery tunica media calcification and myointimal hyperplasia with infantile onset in human beings. NPP1 and PP(i) have the potential to modulate atherogenesis by regulating arterial smooth muscle cell (SMC) differentiation and function, including increase of pro-atherogenic osteopontin (OPN) expression. Hence, this study tested the hypothesis that NPP1 deficiency modulates both atherogenesis and atherosclerotic intimal plaque calcification. Npp1/ApoE double deficient mice were generated by crossing mice bearing the ttw allele of Enpp1 (that encodes a truncation mutation) with ApoE null mice and fed with high-fat/high-cholesterol atherogenic diet. Atherosclerotic lesion area and calcification were examined at 13, 18, 23 and 28 weeks of age. The aortic SMCs isolated from both ttw/ttw ApoE(-/-) and ttw/+ ApoE(-/-) mice demonstrated decreased Opn expression. The 28-week-old ttw/ttw ApoE(-/-) and ttw/+ ApoE(-/-) had significantly smaller atherosclerotic lesions compared with wild-type congenic ApoE(-/-) mice. Only ttw/ttw but not ttw/+ mice developed artery media calcification. Furthermore in ttw/+ mice, there was a tendency towards increased plaque calcification compared to ApoE(-/-) mice without Npp1 deficiency. We conclude that Npp1 promotes atherosclerosis, potentially mediated by Opn expression in ApoE knockout mice

NPP1 inhibits intimal hyperplasia in ApoE knockout mice

Atherosclerosis is an important cause of morbidity and mortality, which is increasingly recognized and reported on a global scale. This pathology is due to multiple metabolic toxicity including increased levels of reactive oxygen species (ROS). Excessive ROS are damaging to proteins, lipids, carbohydrates and nucleic acids, which prompt a classic “response to injury” mechanism including inflammation supporting a cytokine surge, granulation and fibrosis. ROS are excessive, robustly produced in atherosclerosis associated with endothelial dysfunction. Excessive ROS due to osteopontin (OPN) increase may be the driving force promoting atherosclerotic process. Recently has been shown that ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) promotes atherosclerosis, potentially mediated by OPN expression in ApoE knockout mice (Nitschke et al., 2011). Hence, this study tested the hypothesis that NPP1 deficiency modulates intimal hyperplasia and oxidative stress in the atherosclerotic process. For this study were used ApoE null mice and Npp1/ApoE double deficient mice. Atherosclerotic lesion area, calcification and vascular alterations were examined at 13, 18, 23 and 28 weeks of age. Morphological changes in vessels were evaluated by histological procedures and immunohistochemical analysis using thrombospondin-1 (TSP-1), transforming growth factor-β1 (TGF-β1), plasminogen activator inhibitor-1 (PAI-1) and oxidative stress markers such as superoxidodismutase (SOD) and inducible nitric oxide synthase (iNOS). In ApoE null mice vessels we demonstrated vascular alterations with extensive accumulation of collagen and elastic fibers and also an increase of TSP-1, TGF-β1, PAI-1 expression and oxidative stress related protein levels compared to Npp1/ApoE double deficient mice. Moreover, histological analysis showed neointima formation only in ApoE deficient mice. Our findings suggest that NPP1 could be involved in intimal hyperplasia and oxidative stress in the atherosclerosis pathway

Crisponi syndrome/cold-induced sweating syndrome type 2: Reprogramming of CS/CISS2 individual derived fibroblasts into three clones of one iPSC line

Crisponi syndrome/cold-induced sweating syndrome type 2 (CS/CISS2) is a rare disease with severe dysfunctions of thermoregulatory processes. CS/CISS2 individuals suffer from recurrent episodes of hyperthermia in the neonatal period and paradoxical sweating at cold ambient temperatures in adolescence. Variants in CLCF1 (cardiotrophin-like-cytokine 1) cause CS/CISS2. Here, we summarize the generation of three clones of one stem cell line (iPSC) of a CS/CISS2 individual carrying the CLCF1 variant c.321C>G on both alleles. These patient derived iPSC clones show a normal karyotype, several pluripotency markers, and the ability to differentiate into the three germ layers

Cerebral Arterial Stenoses and Stroke: Novel Features of Aicardi-Goutières Syndrome Caused by the Arg164X Mutation in SAMHD1 Are Associated with Altered Cytokine Expression

Aicardi-Goutières syndrome (AGS) is a rare inborn multisystemic disease, resembling intrauterine viral infection and resulting in psychomotor retardation, spasticity and chilblain-like skin lesions. Diagnostic criteria include intracerebral calcifications and elevated interferon-alpha and pterin levels in cerebrospinal fluid (CSF). We report on four adult siblings with unknown neurodegenerative disease presenting with cerebrovascular stenoses, stroke and glaucoma in childhood, two of whom died at the age of 40 and 29 years. Genome-wide homozygosity mapping identified 170 candidate genes embedded in a common haplotype of 8Mb on chromosome 20q11-13. Next generation sequencing of the entire region identified the c.490C>T (p.Arg164X) mutation in SAMHD1, a gene most recently described in AGS, on both alleles in all affected siblings. Clinical diagnosis of AGS was then confirmed by demonstrating intracerebral calcifications on cranial computed tomography in all siblings and elevated pterin levels in CSF in three of them. In patient fibroblasts, lack of SAMHD1 protein expression was associated with increased basal expression of IL8, while stimulated expression of IFNB1 was reduced. We conclude that cerebrovascular stenoses and stroke associated with the Arg164X mutation in SAMHD1 extend the phenotypic spectrum of AGS. The observed vascular changes most likely reflect a vasculitis caused by dysregulated inflammatory stress response. © 2010 Wiley-Liss, Inc

Metabolic control during the neonatal period in phenylketonuria:associations with childhood IQ

Background In phenylketonuria, treatment and subsequent lowering of phenylalanine levels usually occur within the first month of life. This study investigated whether different indicators of metabolic control during the neonatal period were associated with IQ during late childhood/early adolescence. Methods Overall phenylalanine concentration during the first month of life (total "area under the curve"), proportion of phenylalanine concentrations above upper target level (360 mu mol/L) and proportion below lower target level (120 mu mol/L) during this period, diagnostic phenylalanine levels, number of days until phenylalanine levels were 360 mu mol/L during the first month of life negatively correlated with IQ in late childhood/early adolescence. Separately, phenylalanine concentrations during different periods within the first month of life (0-10 days, 11-20 days, 21-30 days) were negatively correlated with later IQ as well, but correlation strengths did not differ significantly. No further significant associations were found. Conclusions In phenylketonuria, achievement of target-range phenylalanine levels during the neonatal period is important for cognition later in life, also when compared to other indicators of metabolic control. Impact In phenylketonuria, it remains unclear during which age periods or developmental stages metabolic control is most important for later cognitive outcomes. Phenylalanine levels during the neonatal period were clearly and negatively related to later IQ, whereas no significant associations were observed for other indices of metabolic control. This emphasizes the relative importance of this period for cognitive development in phenylketonuria. No further distinctions were observed in strength of associations with later IQ between different indicators of metabolic control during the neonatal period. Thus, achievement of good metabolic control within 1 month after birth appears "safe" with respect to later cognitive outcomes

Future treatments for the arteriopathy of ectopic calcification disorders

Ectopic calcification disorders, including Generalized Arterial Calcification of Infancy (GACI) and Pseudoxanthoma Elasticum are rare but impactful on individuals, healthcare and society, with significant associated morbidity, mortality and healthcare costs. Available therapies are not curative and focus on reducing extracellular calcification to limit progression of the arteriopathy that is responsible for much of the morbidity and, in the case of GACI, significant early mortality (approximately 50% in infancy). In this article, current and emerging medical approaches are reviewed and critiqued, including dietary manipulation, phosphate binders, bisphosphonates, tissue nonspecific alkaline phosphatase inhibitors, ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) enzyme replacement, allele-specific therapies, gene therapies, and antibody targeted treatment. Available therapies may limit further arterial calcification, but in GACI in particular, significant calcification can be present at birth, contributing to high infant mortality. This highlights the need for new approaches that aim to reverse established calcification, rather than merely slow its progression. Recently, a promising new class of antibody-targeted nanoparticle therapeutics has emerged that can reverse established arterial calcification in animals, restoring arterial elasticity. In one realization, nanoparticles carry established chelators, such as ethylenediaminetetraacetic disodium acid, to sites of arterial damage, concentrating the impact of the chelator where it is needed and limiting off-target effects. Such drugs would complement existing and emerging therapies, such as ENPP1 enzyme replacement, that slow or prevent progression of calcification, by offering an opportunity to “reset” arterial health in ectopic calcification disorders. At present, ectopic calcification disorders are challenging to treat effectively and carry a high burden of morbidity and mortality, particularly in GACI. Recent drug developments offer good reason to be hopeful for a new era of effective therapeutics that may reverse established arterial disease as well as halt its progression

A randomized placebo-controlled study on the effect of nifedipine on coronary endothelial function and plaque formation in patients with coronary artery disease: the ENCORE II study

Aims Endothelial dysfunction and plaque formation are features of atherosclerosis. Inhibition of L-type calcium channels or HMG-CoA pathway improves endothelial function and reduces plaque size. Thus, we investigated in stable coronary artery disease (CAD) the effects of a calcium antagonist on coronary endothelial function and plaque size. Methods and results In 454 patients undergoing PCI, acetylcholine (10−6 to 10−4 M) was infused in a coronary segment without significant CAD. Changes in coronary diameter were measured and an intravascular ultrasound examination (IVUS) was performed. On top of statin therapy, patients were randomized in a double-blind fashion to placebo or nifedipine GITS 30-60 mg/day and followed for 18-24 months. Blood pressure was lower on nifedipine than on placebo by 5.8/2.1 mmHg (P < 0.001) as was total and LDL cholesterol (4.8 mg/dL; P = 0.495), while HDL was higher (3.6 mg/dL; P = 0.026). In the most constricting segment, nifedipine reduced vasoconstriction to acetylcholine (14.0% vs. placebo 7.7%; P < 0.0088). The percentage change in plaque volume with nifedipine and placebo, respectively, was 1.0 and 1.9%, ns. Conclusion The ENCORE II trial demonstrates in a multi-centre setting that calcium channel blockade with nifedipine for up to 2 years improves coronary endothelial function on top of statin treatment, but did not show an effect of nifedipine on plaque volum

A Specific IFIH1 Gain-of-Function Mutation Causes Singleton-Merten Syndrome

Singleton-Merten syndrome (SMS) is an infrequently described autosomal-dominant disorder characterized by early and extreme aortic and valvular calcification, dental anomalies (early-onset periodontitis and root resorption), osteopenia, and acro-osteolysis. To determine the molecular etiology of this disease, we performed whole-exome sequencing and targeted Sanger sequencing. We identified a common missense mutation, c.2465G>A (p.Arg822Gln), in interferon induced with helicase C domain 1 (IFIH1, encoding melanoma differentiation-associated protein 5 [MDA5]) in four SMS subjects from two families and a simplex case. IFIH1 has been linked to a number of autoimmune disorders, including Aicardi-Goutières syndrome. Immunohistochemistry demonstrated the localization of MDA5 in all affected target tissues. In vitro functional analysis revealed that the IFIH1 c.2465G>A mutation enhanced MDA5 function in interferon beta induction. Interferon signature genes were upregulated in SMS individuals’ blood and dental cells. Our data identify a gain-of-function IFIH1 mutation as causing SMS and leading to early arterial calcification and dental inflammation and resorption

Diagnostic utility of small fiber analysis in skin biopsies from children with chronic pain

Introduction Small fiber neuropathies (SFN) are associated with a reduction in quality of life. In adults, epidermal nerve fiber density (END) analysis is recommended for the diagnosis of SFN. In children, END assessment is not often performed. We analyzed small nerve fiber innervation to elucidate the potential diagnostic role of skin biopsies in young patients with pain. Methods Epidermal nerve fiber density and sudomotor neurite density (SND) were assessed in skin biopsies from 26 patients aged 7 to 20 years (15 female patients) with unexplained chronic pain. The results were compared with clinical data. Results Epidermal nerve fiber density was abnormal in 50% and borderline in 35% of patients. An underlying medical condition was found in 42% of patients, including metabolic, autoimmune, and genetic disorders. Discussion Reduction of epidermal nerve fibers can be associated with treatable conditions. Therefore, the analysis of END in children with pain may help to uncover a possible cause and guide potential treatment options